Most of the existing lighting devices were installed with little consideration of minimizing energy wastage. Very often all the lights inside a room can only be turned on and off together, or dimmed on and off together. Over-illumination happens when only one area of the room requires illumination but other parts of the room are also illuminated because of the inflexibility of the existing lighting device. There are several ways to tackle the problem. One way is to re-install new lighting system having functions similar to stage lighting in order to enable a user to control the illumination of each individual light (i.e. light output, beam size and beam direction). However, the high cost of installation will prohibit most users from doing it this way. Another way is to install a do-it-yourself type home automation product which has a remote control unit for controlling each plug-in lamp to operate at on/off/dimming modes independently with an intermediate adaptor between a plug-in lamp and a wall power socket. Lighting fixtures can be controlled in groups with the wall mounted dimming control units. However, it is rather complicated for a user to install this do-it-yourself type lighting product. Hence, there is a need to produce an improved adjustable lighting device that is simple, easy to install, and less expensive.
The above description of the background is provided to aid in understanding an adjustable lighting device, but is not admitted to describe or constitute pertinent prior art to the adjustable lighting device disclosed in the present patent application, or consider any cited documents as material to the patentability of the claims of the present patent application.